Note: Descriptions are shown in the official language in which they were submitted.
CA 02526993 2005-11-25
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~0 Auta~atic sun position follow-up jeans
The present invention is directed to an automatically
functioning sun position follow-up means for solar modules.
It is known to guide solar modules (solar collectors, solar
panels etc.) in response to the position of the sun in
order to enable an optimum exposure to sunlight. ~vrmally,
it is desired to obtain a vertical impingement of the
sunlight onto the plane of the solar module which assures
the optimum energy yield. If this is not the case, i.e. i~
the sunrays impinge onto the plane of the solar module with
a smaller angle or with a larger angle than 90°, the energy
yield is lower.
Since, according to the time of the day, different angles
of incidence of the sunrays are present the solar module
has to follow the position of the sun. this can be carried
out manually which, however, is troublesome and time
consuming. However, already automatically functioning sun
3o position follow-up means for solar moduJ.es axe known
according to which the position of the sun is detected by
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means of a sensor, corresponding signals are genErated in
response Lhereto and are supplied to a controi unit, and
the control un9.t controls respective drive units for the
solar module in response to these signals in order to move
the solar modul into an optimum position with regard to the
sun.
It is the object of the present invention to provide an
automatically functioning sun position follow-up means for
1o solar modules which is characterized by a compact and
sturdy construction with small need of maintenance.
According to the invention this object is achievEd by an
automatically functioning sun position follow-up means for
IS solar modules comprising
a base for mounting the means at a stationary ox movable
part, especially a vehicle;
20. a rotary plate rotationally supported on the base and
driven by means of a rotary drive;
a pivot frame pivotally supported on the rotary plate and
driven by means of a pivot drive and having supported
zs thereat at least one solar module; and
an optosensor generating signals an response to the
position of the sun and supplying the same to a control
unzt which controls the rotary drive and/or pivot drive;
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wherein the pivot frame includes at least one member
fixedly connected to the rotary plate and a p3.vot member
pivotally supported at said one member and carrying the
solar module, the pivot drive is supported in the end
portion of the member which is fixedly connected to the
rotary plate transversely with respect to the axis thereof
and does not protrude beyond this member upwardly, and the
pivot drive includes a motor, a reducing transmission and a
transmission output shaft provided with a toothing and with
ao which a sector gear connected to the pivot member of the
pivot frame is in engagement.
With the inventive sun position follow-up means it is
possible to turn one or a plurality of solar modules (solar
is collectors. solar panels) about a vertical axis and to
pivot the same about a horizontal axis. By this, the solar
module or the solaz modules can be brought into a position
in which the sunrays substantially vertically impinge onto
the plane of the modules so that in this manner an optimum
2o energy conversion (into electrical current) can be
obtained. The movement of the solar module or of the solar
modules takes placE automatically in response to the
' position of the sun wherein an optosensor detects the
position of the sun, generates corresponding signals and
25 supplies the same to the control unit. The control unit
controls the rotary drive and/or pivot drive which generate
the necessary movements of the solar module or the solar
modules about the vertical axis and/or the horizontal axis
for the follow-up of the sun position.
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The inventive sun position follow-up means can be fastened
to a stationary or. to a movable part. In an especially
prcEerred manner it serves for the fastening to a vehicle,
for instance a mobile home or a caravan, especially on the
roof of the same. The solax module or the solar modules can
take over the current supply of the mobile home or the
caravan.
The inventive sun position followJup means has a base for
i0 mounting to the stationary or movable part and a rotaxy
p ate rotatably supported on the base and driven by a
rotary dxive. A rotary movement of the rotary plate and
thus of the solar module or of the solax modules about a
vertical axis of rotation takes place by means of the
rotary drive which is controlled by the control unit. A
pivot frame is disposed on the rotary plate which pivot
frame can be pivoted up and is brought into the
corresponding pivot position by means of a pivot drive. The
solar module or the solar modules are fastened to the pivot
frame. The pivot frame can be moved from a position
parallel with respect to the rotary plate (with a pivot
angle of 0°) into a pivot-up position of about 90° and back
again.
On principle, the pivot frame has a member fixedly
connected to the rotary plate and a pivot member pivotally
supported at this member and carrying the solar module or
the solar modules. It is essential that the pivot drive,
which is disposed in the end portion of the member fixedly
connected to the rotary plate, i.e. in the end portion in
which the pivot bearing between the two members is
CA 02526993 2005-11-25
provided, substantially does riot protrude beyond the upper
side of the member fixedly connected to the rotary plate in
order to make it possible that Solar modules can bE
arranged along the whole length of the members and, on the
s whole, a low height of construction is achieved according
to which no mechanical parts protrude upwardly in the
pivot-down condition. ay this, the whole area above the
members can be used for the arrangement of solar modules,
and low moments occur when pivoting up. Furthermore, the
wind forces attacking the means are reduced which is
especially of importance for the arrangement of the sun
position follow-up means on the roof o~ a vehicle.
This desired compact construct~.on is especially achieved by
the design and arrangement of the pivot drive. the pivot
drive is supported at the member fixedly connected to the
rotary plate transversely with respect to the axis
(longitudinal axis) thereof and ~.ncludes a motor, a
reducing transmission and a transmission output shaft
provided with a toothing wherein a sector gear connected to
the pivot member of the pivot ~xame engages the output
shaft. The sector gear is designed and arranged in such a
manner that it does not protrude beyond the pivot member
upwardly. This would be the case with a normally designed
gear with complete circle.
When the motor (electrical motor) of the pivot drive is
controlled the shaft thereof is rotated. By the used
txansmisszon a gear reduction is achieved, preferably with
3o a ratio of about 1:180. Accordingly, the output shaft of
the transmission rotates substantially more slowly than the
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motor shaft and pivots the sector gear matching with the
same and thus the pivot member with the solar module (sola.r.
modules) fixed therEto.
s Preferably, the sector gear covers an arc of about 120°,
i.e. a third of a circle. Sy this, the desired pivoting of
the pivot member for at least 90° can be obtained without
having an upward protrusion of the sector gear beyond the
members and without making impossible the arrangement of
solar modules in this range.
According to a further development of the invention the
pivot member with the sector gear is supported between two
members fixedly connected to the rotary plate in a manner
adapted to be pivoted upwardly. Zn this manner, a support
of the p~.vot member with sector gear on both sides and thus
a sturdy arrangement of the same is achieved. Practically,
the motor, the reducing transmission and the transmission
output shaft are supported at two members fixedly connected
2o to the rotary plate which have between them the toothing of
the transmission output shaft. By this, a sturdy design of
the pivot drive is achiEVed, either.
For example, the member fixedJ.y connected to the rotary
z5 plate and the pivot member can be farmed as plate-like or
rod-like members. The transverse extension of these members
does not have any restrictions. Normally, the pivot frame
extends beyond the rotary plate an lateral direction.
According to a preferred embodiment the members are formed
3o as rods, i_e. the pivot frame includes at least one rod
fixedly connected to the rotary plate and at least one
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pivot rod. According to a special embodiment the means
includes four rods fixedly connected to the rotary plate of
which the two outer ones are pivotally connected to a
rESpective pivot rod and the two inner ones are pivotalJ.y
s connected to the pivot rod having the sector gear.
Especially, two solar panels are fastened to the pivot rods
and realize the connection between the driven pivot rod
(the pivot rod provided with the sector gear) and the two
other pivot rods.
Accordingly, the pivot frame, the pivot drive and the
rotary plate form a unit rotationally supported on the
base. Preferably, the rotary plate is rotatably supported
on the base by means of balls disposed in an annular
1s groove .
Preferably, the base consists of a bottom plate, a housing
arranged thereupon and a fixed plate arranged thereupon for
the support of the rotary plate. 'fhe annular groove is
2o disposed in the fixed plate with one half and in the rotary
plate with the other half. For 'example, the bottom plate
can be connected by screwing, bonding etc. to the roof o~ a
vehicle (mobiJ'e home, caravan). ~xactically, in the housing
arranged on the bottom plate the rotary drive is housed
2s which has a motor (electrical motor), a reducing
transmission and a drive screw which ,is in engagement with
a drive gear for the rotary plate. The drive gear is
connected to a hollow hub which extends through the fixed
plate and is connected to the rotary plate.
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Suitable limit switches limiting the angle of rotation or
the pivot angle are provided for the rotary drive and for
the pivot drive.
Preferably, the optosensox is disposed at the solar module
(solar panel). Furthermore, the pivot frame preferably
carries two solar panels of which the upper one in the
pivot position carries the optosensor. The optosensor and
the limit switches for the rotary drive and pivot drive
supply corresponding signals to a control unit (CPU) which
controls the two motors for the pivot drive and rotary
drive as well as ys in functional connection with an
operation panel with display which enables at least a
manual switching-on and switching-off of the means and has,
for example, a display with luminescence diodes which
indicates the correct position of the means rElative to the
position of the sun.
The optosensor enables an especially exact detection of the
position of the sun with a simple and compact construction.
Preferably, it comprises the following components:
a base,
a separation means arranged on the base and separating the
space above the base in a plurality of upwardly and
laterally open compartments,
at least one light receiving means in each compartment
which converts light into electrical current, and
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electrical lines connected to the light receiving means and
leading to a control/evaluationjdisplay unj.t.
This design is based on the basic idea to provide with the
separation means disposed on the base a means which throws
a shadow in response to the position of the sun which
covers one compartment or a plurality of compartments and
thus the at least one light receiving means disposed in
each compartment. Accordingly, dependent on the position of
1o the sun the separation means can generate no shadow at all
if the sun is positioned exactly vertically above the
sensor and thus above the separation means or if, moreover,
equal light conditions are present, as fox instance zn the
night, with diffuse light etc., or the separation means can
throw a shadow iF its longitudinal axis forms an angle with
the axis corresponding to the position of the sun. Zn this
case, one compartment or a plurality of compartments and
thus the corresponding light receiving means of the
associated compartments are covered by the shadow generated
by the separation means and thus do not generate electrical
signals while the other compartments and associated light
receiving means are free of shadow and generate electrical
signals.
The electrical signals are supplied to a control unit
which, in response to the received signals, operates the
rotary drive and/or pivot drive which guide the solar
module relative to the position of the sun, i.e. bring it
into an optiumum position w5.th respect to the sun, in which
3o the sunrays impinge approximately vertically onto the
surface of the solar module (surface of the Solar panel).
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Of course, the corresponding electrical signa7.s are
evaluatEd in a suitable manner before they .fulfill their
control functions.
If, for instance, the sensor and thus the separation means
is aligned in such a manner that the axes of the sensor and
o~ the separation means extend exactly parallel with
rESpect to the sunrays at the highest position of the sun
(noon), in this case all the light receiving means are in
to operation with a corresponding sun radiation and show the
optimum position of the sun. Accordingly, a movement of a
corresponding solar module is not necessary. If the angle
of the sun radiation relative to the axis of the sensor
changes now the separation means throws shadow onto one or
several compartments so that one or several light receiving
means axe set out of operation which, as cited above, is
indicated or results in a follow~up of the corresponding
solar module until the optimum position is achieved agap.n.
Preferably, the separation means divides the space above
the base in four compartments. It forms a so-called 'shadow
cross" with which especiaJ.ly good results are obtained with
regard to the operability of the sensor.
Pratically, a light rECeiving means is arrangEd in each
compartment. This arrangement is sufficient a.n order to
provide a sufficiently exact indication and control.
Preferably, a photodiode is used as light receiving means.
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For the practice an embodiment has shown to be especially
suited according to which the sensor has an approximately
square base in horizontal cross-section and a separation
means with walls arranged along the diagonals of the base.
Accordingly, the separation means forms a "shadow cross"
approximately corresponding to a St. Andrews cross in
horizontal cross-section. Four triangular compartments are
formed in which a respective photodiode is disposed with a
suitable distance from the walls of the shadow cross. The
to photo diodes are fixed at the base wherein the
corresponding electrical lines axe combined within the base
and extend outwardly o.f the base through an electrical
cable. The cable is in connection with a suitable
control/evaluation/display unit.
Practically, the sensor is provided at the solar module
itself which is rotatably and pivotally arranged, i.e. it
is co-moved into the optimum position of the solar module
relative to the sun. Accordingly, the position of the
2o sensor always exactly corresponds to the position of the
solar module.
It can be generally stated: If all the light receiving
means are illuminated with the same intensity (with sun
radiation, diffused light, during the night) the associated
control unit does not generate commands for the follow-up
of the solar module. Such control commands are generated
only if brightness d.ifferEnces occur between the several
compartments (light .receiving means). If such a difference
occurs, preferably both drive means, i.e. the rotary drive
and the pivot drive, are controlled (in a zigzag course) in
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order to obtain a vertical position of the sun. Preferably,
such a control un.~t is provided with a means for the
suppression of oscillations in order. to avoid a permanent
movement of the drive means fore and back.
In the following the invention is described by means of an
example in connection with the drawings in detail. Of the
drawings
1o Fzgure Z shows a vertical section through an
automatically operating sun pos~.tion folJ.ow~
Up means for solar modules;
Figure 2 shows a top view on the housing of the means
of .figure 7. with removed cover;
Figure 3 shows a top view of the means of figures 1
and 2;
z0 Figure ~1 shows a detailed view of a part of the pivot
drive;
Figuz~Q 5 shows a schematical side view of an
optosensor ,for the detection of the position
of the sun;
Figure & shows a top view of the sensor of figure 5;
and
3o Figure 7 shows a block cixcuit diagram of a sun
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positzon follow-up means in which the sensor
of figures 5 and 6 is used.
The sun position follow-up means for solar modules shaven in
s fzgure 1 has a base cansisting of a bottom plate 1, a
housing 2 and a plate 3 disposed on the housing. A rotary
plate 9 is rotatably supported on the base and carries a
pivot frame 31 at which two solar panels 13 are fastened.
ThESe solar panels 13 convext sunlight into electrical
io cuxxent which, for instance, can serve for the supply of a
vehicle on the roof of which the means is arranged.
For the installation of the means the bottom plate 1 is
bonded or screwed to the roof of the vehicle. Dependent on
1s signals generated by an optosensor 19 which is disposed at
the upper solar panel 13 in the figure a rotary drive for
rotating the xotary plate 4 and a pivot drive for upwardly
and downwardly pivoting the pivot frame 31 are operated in
oxder to adjust an optimum condition of the solar panels 13
zo relative to the sun (vertical impingement of the sunrays
onto the panel plane).
The rotary drive for the rotatzon of the xotary plate 4 is
disposed in the housing 2 arranged on the bottom plate 1.
z5 The rotary drive comprisES an electrical motox 16, a
reducing transmission 15 and a drive screw 9 which axe
arranged along an axis. the screw 9 is in engagement with a
drive gear $ which is fixedly connected to a hollow hub 7.
The hollow hub extehds upwardly through the fixedly
3o installed plate 3 and is fixedly connected to the rotary
platE 9. Accordingly, a rotation of the drive gear 8
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generated by the drive screw 9 causes a rotation of the
rotary plate 9. The rotary plate 4 is supported on the
fixed plate 3 by means of balls 5 which are housed in an
annular groove 6 which extends J.n both plates 3, 4 with a
half .
The rotation of the drive gear 8 is limited by limit
switches 18 which are contacted by a lever 17 which is
guided through a mandrel in a screw groove disposed at the
t0 lower side of the drive gear 8. Accordingly, the drive gear
8 can carry out a rotation for 370° from abutment to
abutment.
Furthermore, a box 10 zs arranged within the housing 2 and
~s houses a control unit 10 controlling the rotary drive and
the pivot drive and to which corresponding signals by the
limit switches of the rotary drive and the pivot drive as
well as by the optosensor are supplied. Furthermore, the
control unit IO is in connection with an operation panel
2o with display. The corresponding electrical lines herefor
are not shown.
The pivot drive for upwardly and downwardJ.y pivoting the
pivot frame 31 is only schematically shown in figure 1 with
25 30. A more exact deseziption of the pivot drive follows in
GOnnection with figures 3 and 9.
If a signal of the optosensor 14 is supplied through the
control. unit J.0 which makes necessary a follow-up of the
3o means by a rotary movement of the rotary plate 9, the motor
16 ~.s controlled by the control unit 10. The output shaft
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of the motor is rotated by this. A corresponding gear
reduction is carried out by the transmission 15 so that the
drive screw 9 has a substantially lower speed. The drive
scrEw 9 drives the drive gear 6 in the selected direction.
5 The rotation of the same results in a rotation of the
rotary plate 4 in a manner determined by the control of the
control unit or by the limit switches 18. The rotary plate
9 is rotated fore and back as long as it takes in the
optimum rotary position for the position of the sun.
Figure 3 shows a top view of the rotary plate 9 on which
the pivot frame 31 is fastened. The two solar panels 13
which axe fixed at the pivot frame are only shown with
dashed lines.
The pivot frame has two outer pivot rods 13 which are
pivotally connected to a rod 11 fixedly connected to the
rotary plate 9, as shown at 32. Furthermore, the pivot
frame has a third approximately centrally arranged pivot
rod 20 which is connected to the pivot drive and is thus
pivoted. zts pivot movement is transferred through the
solar panels 13 onto the two outer pivot rods 13. The
central pivot rod 20 is pivotally connected to two inner
rods 19 fixedly connected to the rotary plate 4.
Accordingly, on the whole seven rods are provided, namely
three pivot rods and four fixedly installed rods. The two
solar panels 13 are fastened at the three pivot rods 13 and
20_
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Furthermo.r.e, the central pivot rod 20 is connected to a
sector gear 25 which approximately corresponds to a third
of a circle. This sector gear 25 and also the further parts
of the pivot drive do not protrude beyond the upper sides
Of the pivot x'ods so that the solar panels cover 'the pivot
dr~.ve and can extend along the whole length of the pivot
rods. By th~.s, in the collapsed condition of the pivot
frame no parts protrude upwardly beyond the rod, and solar
panels with an area as large as possible can be installed.
As shown in the detailed view of figure 9 the sector gear
25 J.s in engagement with the toothing of a transmission
output shaft 26 of the pivot drive. By rotation of the
shaft 26 the rod 20 is pivoted up and down whereby the
IS solar panels are brought into the optimum position relative
to the sun. The transmission output shaft 26 extends out of
a reducing transmission 22 which is connected to a drive
motor (electrical motor) 24 through another reducing
transmission 23. The motor 29, the two reducing
transmissions 23 and 22 and the transmission output shaft
26 axe arranged along an axis. The whole drzve means i.s
flanged to the stationary rod 19, as shown at 21. The
transmission output shaft is supported at the two
stat~.onary rods 19 by means of suitable bearing blocks (not
shown) .
zf the pivot motor 24 is controlled by the control unit J.0
zts output shaft is rotated. A gear reduction of about
1:180 ~.s obtained by the two reducing transma.ssions 23 and
22 which results in a reduced rotary movement of the
toothed transm~.ssion output shaft 26. The same is in
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engagement with the sector gear 25 and brings Che pzvot rod
20 and ~ct~us the solar panels 13 in the desired pivot
position zn this manner. Pivoting back is carried out v~.ce
versa. Suitable limit switches are also provided for
limiting the pivot movement of the pivot frame.
Accordingly, an automatically operating sun position
follow-up means for solar modules is described according to
the invention which is largely maintenance--free on account
of its mechanical, drive and which has a very compact
construction. Accordingly, solar panels with a large
surface can be arranged, and the means does only generate a
small wend resistance. A low construction height is
obtained. The means is formEd in an especially sturdy
IS manner.
The optosensor shown in figures 5 and 6 has a base 100
which is only schematically shown as a corresponding
pedestal. Its base is designed hollow in order to take-up
zo corresponding wirings. On its lower side it has a cable
outlet. According to this embodiment the base is
approximately square zn horizontal cross-section.
A separation means 200 is disposed on the base 100. In a
zs horizontal cross-section the separation means has the shape
of a St. Andrews cross. The, separation means 200 forms four
compartments 160 which, axe triangular in horizontal cross-
section and which axe upwardly and laterally open.
Accordingly, sunlight can enter these compartments from
3o above and from the szde_ 'the two other sides of the
triangle which co.rr_espond to the diagonals~of the base are
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1R
occupied by the wa)_Is 600 of the separation means 200 and
thus shield the rESpective Compartment with regard to
sunligt.
A light receiving mEans 300 formed as photodiode is
disposed in evEry compartment in a suitable distance from
the separation means 200. Upon radiation with sunlight the
photodiode 300 generates electrical signals which are
supplied to an appropriate control unit through electrical
conductors 400 which are combined in an electrical cable
500.
The separation means 200 has a suitable height in order to
enable a shadow throw of the separation means 200 auto one
t5 compartment or a plurality of compartments and thus onto
the ligth receiving means 300 disposed there upon an
inclined position of the sun relative to the vertical axis
of the sensor. The exact height can be determined
empirically.
Figure 7 shows the sensor of figures 5 and 6 as part of a
sun position follow-up means. The sensor is indicated at
800 and is disposed at the rotatably and pivotally movable
solar module. The corresponding signals of the sensor 800
2s are supplied to a control unit 700 (central processing
unit, CPU) which also receives signals from the switches
900, 1000 of the .rotary drive and pivot drive, evaluates
the received signaJ.s and outputs corresponding control
command signals to the rotary drive 110 as well as the
pivoC drive 120. Furthermore, the con trol unit 700 supplp.es
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signals to an indicating/operating uniC 130. This unit has
a display 140 and an on/off-switch 150.
The wholE means operates as follows:
The user switches on the means with the switch 150. The
sensor 800 detects the position of the sun and applies
corresponding szgnals to the control unit 700. These
signals axe shown in the dispJ.ay 140. Furthermore, by this,
to if necessary, corresponding command signals are genErated
which are supplied to the rotary drive 110 and/or the pivot
drive 120 which cause a follow-up of the solar module. The
provided limit switches 900, 1000 terrnznate the
corresponding movements of the solar module.
~5
25
